Various computers are usually employed in monitoring and control systems associated with high power sources. Conceptually, sensing and actuation devices interfaced to a computer as controlled by the computer software could provide reverse current protection. However, the response time of such a system is generally considered as not fast or reliable enough to provide the desired level of protection.
It is common to use a diode to allow electric current to flow in one direction but not the other. Furthermore, it is common to use diodes to isolate and effectively “OR” DC power sources connected in parallel. High current power sources are often expensive and may be dangerous if damaged or destroyed. If a reverse current protection diode fails in a “shorted” condition, protection of the power source is lost.
A bus fuel cell used to power an electric motor of a bus supplies high-current, high-voltage power to the electric motor through output power wiring. The output power wiring works in parallel with battery energy storage to supply power to an inverter that controls and powers the electric motor that propels the bus. If any condition arises that causes a reverse current into the fuel cell, significant and very expensive damage to the fuel cell may occur. To prevent this, a high current (e.g., 400 amp) diode may be used in series with the fuel cell power circuit. However, as mentioned above, if the diode fails, the expensive fuel cell is no longer protected from reverse-current damage.